A busload of campers stopped at a dairy stand for ice cream

A busload of campers stopped at a dairy stand for ice cream. They orderd 78 cones, some soft-serve at $1.50 each and the rest hard-pack at $0.50 each. If the total bill was $72.00, how many of each type of cone were orderd?

How many soft-serve cones were orderd??

Solution

Let \' x\' and \'y \' represent the number of soft -serve and hard-pack

hence the 2 equations are x + y = 78 ---------(1)

1.50 x + 0.50 y = 72 -------(2) multiply (2) by 2

3 x + y = 144--------(3)

( 3) -- (1) implies 2x = 144 - 78 = 68 therefore x = 34 and y = 78 - 34 =44

Ans x=34 and y = 44